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WO1995015935A1 - Process and device for cleaning vinyl chloride - Google Patents

Process and device for cleaning vinyl chloride Download PDF

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Publication number
WO1995015935A1
WO1995015935A1 PCT/EP1994/004050 EP9404050W WO9515935A1 WO 1995015935 A1 WO1995015935 A1 WO 1995015935A1 EP 9404050 W EP9404050 W EP 9404050W WO 9515935 A1 WO9515935 A1 WO 9515935A1
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WO
WIPO (PCT)
Prior art keywords
vinyl chloride
water
distillation stage
chloride
hydrogen chloride
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP1994/004050
Other languages
German (de)
French (fr)
Inventor
Peter Schwarzmaier
Peter Kammerhofer
Manfred Stöger
Helmut Kalliwoda
Ingolf Mielke
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hoechst AG
Original Assignee
Hoechst AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to RU96115265A priority Critical patent/RU2136651C1/en
Priority to UA96072650A priority patent/UA40639C2/en
Priority to RO96-01138A priority patent/RO117313B1/en
Priority to PL94314878A priority patent/PL177175B1/en
Priority to KR1019960702980A priority patent/KR100336932B1/en
Priority to EP95902128A priority patent/EP0733031B1/en
Priority to DE59405663T priority patent/DE59405663D1/en
Priority to JP7515968A priority patent/JPH09506362A/en
Application filed by Hoechst AG filed Critical Hoechst AG
Priority to AU11098/95A priority patent/AU1109895A/en
Priority to HU9601545A priority patent/HU219385B/en
Publication of WO1995015935A1 publication Critical patent/WO1995015935A1/en
Priority to BG100576A priority patent/BG62484B1/en
Priority to NO962107A priority patent/NO305550B1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00Preparation of halogenated hydrocarbons
    • C07C17/25Preparation of halogenated hydrocarbons by splitting-off hydrogen halides from halogenated hydrocarbons
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00Preparation of halogenated hydrocarbons
    • C07C17/38Separation; Purification; Stabilisation; Use of additives
    • C07C17/383Separation; Purification; Stabilisation; Use of additives by distillation
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00002Chemical plants
    • B01J2219/00004Scale aspects
    • B01J2219/00006Large-scale industrial plants

Definitions

  • 1,2-dichloroethane at elevated pressure of preferably 8 to 40 ata and temperatures between about 450 and 650 ° C in the absence of catalysts, the resulting reaction mixture, the gas mixture leaving the gap zone, which consists of vinyl chloride, hydrogen chloride, unreacted 1,2-dichloroethane and by-products exist, partially condensed in a first distillation stage for distilling off the hydrogen chloride and then passed into a second distillation stage for distilling off the vinyl chloride, after which the bottom product of the second distillation stage is worked up in a known manner for recycling the unreacted 1,2-dichloroethane, and wherein that is drawn off and liquefied at the top of the second distillation stage
  • Vinyl chloride is partially pumped back to about the middle of the first distillation stage, which is characterized in that the liquefied vinyl chloride withdrawn as production, which still contains small amounts of hydrogen chloride, is fed to the top of a degassing zone from which a part of the vinyl chloride is combined using a circulation evaporator evaporated with the entire introduced hydrogen chloride, condensed and about in the middle of the the first distillation stage provided for distilling off the hydrogen chloride is pumped back while the purest vinyl chloride is removed from the bottom of the degassing zone.
  • the known method is disadvantageous when the vinyl chloride fed to the degassing zone still contains small amounts of water. In practice, these are inevitable; traces of water are inevitably introduced, especially when the system is started up and in the event of operational interruptions.
  • the degassing zone was then operated in such a way that these amounts of water were removed via the bottom of the degassing column, together with hydrogen chloride, for which the sodium hydroxide-filled towers were required again. If this separation of the water via the bottom of the degassing column were not carried out, the water would be circulated with the recycled vinyl chloride and would lead to corrosion in the plant parts concerned. However, such corrosion is unacceptable not only for economic reasons, but above all for safety reasons.
  • the invention thus relates to a process for the production of vinyl chloride, which is characterized in that from the reaction mixture obtained in the incomplete thermal cleavage of 1,2-dichloroethane at elevated pressure and temperatures of about 450 to about 650 ° C. in the absence of catalysts in a first distillation stage, the hydrogen chloride and in a second distillation stage the vinyl chloride is distilled off, and the vinyl chloride drawn off and liquefied at the top of the second distillation stage is partly returned as reflux to the second distillation stage and the remaining liquefied vinyl chloride withdrawn is fed to the top of a degassing zone from which a portion of the vinyl chloride together with all of the hydrochloric acid and water introduced is evaporated off and, after the water has been largely removed, is returned to the first distillation stage while removing pure vinyl chloride from the bottom of the degassing zone will come.
  • the invention further relates to a device for producing vinyl chloride with a cracking zone (1), a first distillation stage (2) for the removal of hydrogen chloride and a second
  • the device according to the invention is shown schematically in the figure.
  • they mean:
  • the extensive removal of water according to the invention can be carried out in the manner known for acidic fluids. This can be done by condensing the water, but preferably by drying, for example with agents that undergo chemical conversion, for example liquid drying agents such as concentrated sulfuric acid or solid drying agents such as phosphorus pentoxide or calcium chloride. Drying agents which retain the water by adsorption, such as molecular sieves and in particular silica gels, are preferred.
  • the drying zone preferably consists of at least two dryers connected in parallel, the one containing the water-containing mixture to be recycled being passed through, while the other (or the others) is being regenerated or newly loaded. It is of course also possible to operate several drying devices in series. The valuable substances released during the regeneration, vinyl chloride and hydrogen chloride, can be returned to the process.
  • the drying apparatus are designed so that they are used for Regenerate heated and flushed with an inert gas such as carbon dioxide, an inert gas or preferably nitrogen.
  • an inert gas such as carbon dioxide, an inert gas or preferably nitrogen.
  • Tubular heat exchangers or containers with internal coils are suitable, for example.
  • the gas stream discharged via the top of the degassing column can be dried or the top product condensed and the condensate passed through the dryer or dryers.
  • the dryers are expediently installed as close as possible to the degassing zone, since the top of this column has the greatest water concentration - especially when the gas phase is to be dried.
  • the dryer can be installed at the beginning of the vapor line.
  • sodium hydroxide towers and the like can be dispensed with, this includes
  • the invention naturally also includes embodiments in which such devices are retained, for example for safety reasons. In this case, these devices have a significantly longer service life and a correspondingly reduced amount of salt and waste water.
  • a stream of vinyl chloride of 39 kg / h with an average water content of 29.5 ppm is fed through a tube (length 200 mm, diameter 80 mm), filled with a wire mesh with a mesh size of 125 ⁇ m, and charged with 740 g of silica gel (commercially available M Blaugel • ", small pores, 1 to 3 mm grain size), pumped (pressure at
  • Low-pressure steam is passed through the apparatus for desorption. After 180 minutes, the residual loading of the silica gel is ⁇ 0.3%.
  • a vinyl chloride flow of 39 kg / h is passed through a cylindrical container for 19 hours. Dimensioning and loading correspond to the rest of the container described in Example 1. After a running time of 19 hours, the loading of the silica gel is 3.07% by weight. The water content of the dried vinyl chloride is 6.5 ppm. For regeneration, the container is heated to approximately 120 ° C. (internal temperature), a nitrogen stream of 100 l / h being passed through the apparatus. After 3 hours, the loading of the silica gel is 0.25%.
  • a vinyl chloride stream of 34 kg / h with an average water content of 30 ppm is fed through a tube (length 200 mm, diameter 80 mm), filled with molecular sieve (WESSALITH US 330, Degussa, Hanau), with a pressure of pumped about 16 bar.
  • WESSALITH US 330, Degussa, Hanau molecular sieve
  • the molecular sieve has adsorbed 738 g of water, which corresponds to a loading of 31.9% by weight, based on the adsorbent.
  • the residual loading is approximately 13% by weight.
  • the drying device consists of a tube 200 mm long and 15 mm in diameter. It is filled with 35 g of silica gel (commercially available "Blaugel 11 , narrow-pored, 1 to 3 mm grain size). After 100 l of the gas stream mentioned had been passed through this dryer, the loading of the drying agent was 12.8% by weight. The escaping gas contained an average water content of 0.5 ppm.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Drying Of Gases (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)

Abstract

In the production of vinyl chloride by the thermal splitting of 1,2-dichloroethane, first of all hydrogen chloride, then vinyl chloride and finally hydrogen chloride taken along with vinyl chloride are distilled off in three stages. If water carried over in the final stage is not drained off through the bottom of the stage, it is taken back with the head product into the first stage and causes corrosion. Removal of the water at the head of the third distillation stage, preferably by drying, prevents corrosion.

Description

Beschreibung description

Verfahren und Vorrichtung zur Reinigung von VinylchloridProcess and apparatus for cleaning vinyl chloride

Aus der US-Patentschrift 3 843 736 ist ein Verfahren bekannt zur Gewinnung von Vinylchlorid aus dem bei der unvollständigen thermischen Spaltung vonA process is known from US Pat. No. 3,843,736 for the production of vinyl chloride from the incomplete thermal cracking of

1,2-Dichlorethan bei erhöhtem Druck von vorzugsweise 8 bis 40 ata und Temperaturen zwischen etwa 450 und 650 °C in Abwesenheit von Katalysatoren anfallenden Reaktionsgemisch, wobei die die Spaltzone verlassende Gasmischung, welche aus Vinylchlorid, Chlorwasserstoff, nicht umgesetztem 1,2-Dichlorethan sowie Nebenprodukten besteht, teilweise kondensiert in eine erste Destillationsstufe zur Abdestillation des Chlorwasserstoffs und anschließend in eine zweite Destillationsstufe zur Abdestillation des Vinylchlorids geleitet wird, wonach das Sumpfprodukt der zweiten Destillationsstufe zwecks Rückführung des nicht umgesetzten 1,2-Dichlorethans in bekannter Weise aufgearbeitet wird und wobei das am Kopf der zweiten Destillationsstufe abgezogene und verflüssigte1,2-dichloroethane at elevated pressure of preferably 8 to 40 ata and temperatures between about 450 and 650 ° C in the absence of catalysts, the resulting reaction mixture, the gas mixture leaving the gap zone, which consists of vinyl chloride, hydrogen chloride, unreacted 1,2-dichloroethane and by-products exist, partially condensed in a first distillation stage for distilling off the hydrogen chloride and then passed into a second distillation stage for distilling off the vinyl chloride, after which the bottom product of the second distillation stage is worked up in a known manner for recycling the unreacted 1,2-dichloroethane, and wherein that is drawn off and liquefied at the top of the second distillation stage

Vinylchlorid teilweise etwa in die Mitte der ersten Destillationsstufe zurückgepumpt wird, das dadurch gekennzeichnet ist, daß man das als Produktion abgezogene, verflüssigte Vinylchlorid, das noch geringe Mengen Chlorwasserstoff enthält, dem Kopf einer Entgasungszone zuführt, aus der mittels eines Umlaufverdampfers ein Teil des Vinylchlorids zusammen mit dem gesamten eingeschleppten Chlorwasserstoff abgedampft, kondensiert und etwa in die Mitte der ersten, zur Abdestillation des Chlorwasserstoffs vorgesehenen Destillationsstufe zurückgepumpt wird, während dem Boden der Entgasungzone reinstes Vinylchlorid entnommen wird.Vinyl chloride is partially pumped back to about the middle of the first distillation stage, which is characterized in that the liquefied vinyl chloride withdrawn as production, which still contains small amounts of hydrogen chloride, is fed to the top of a degassing zone from which a part of the vinyl chloride is combined using a circulation evaporator evaporated with the entire introduced hydrogen chloride, condensed and about in the middle of the the first distillation stage provided for distilling off the hydrogen chloride is pumped back while the purest vinyl chloride is removed from the bottom of the degassing zone.

In dieser Patentschrift wird auch erwähnt, daß die geringen Mengen des Chlorwasserstoffs, die in der Entgasungszone entfernt werden, früher mit Hilfe von Türmen, die mit Natriumhydroxid gefüllt waren, abgetrennt wurden.This patent also mentions that the small amounts of hydrogen chloride removed in the degassing zone were previously separated using towers filled with sodium hydroxide.

Das bekannte Verfahren ist jedoch dann nachteilig, wenn das der Entgasungszone zugeführte Vinylchlorid noch geringe Wassermengen enthält. Diese sind in der Praxis unvermeidlich; vor allem beim Anfahren der Anlage und bei Betriebsunterbrechungen werden zwangsläufig Spuren von Wasser eingebracht. In der Praxis wurde deshalb dann die Entgasungszone so betrieben, daß diese Wassermengen über den Sumpf der Entgasungskolonne - zusammen mit Chlorwasserstoff - abgetrennt wurden, wofür die Natriumhydroxid-gefüllten Türme doch wieder erforderlich wurden. Würde diese Abtrennung des Wassers über den Sumpf der Entgasungskolonne nicht durchgeführt, so würde das Wasser mit dem zurückgeführten Vinylchlorid im Kreislauf geführt und in den betroffenen Anlageteilen zu Korrosionen führen. Solche Korrosionen sind jedoch nicht nur aus wirtschaftlichen, sondern vor allem aus Sicherheitsgründen nicht hinnehmbar.However, the known method is disadvantageous when the vinyl chloride fed to the degassing zone still contains small amounts of water. In practice, these are inevitable; traces of water are inevitably introduced, especially when the system is started up and in the event of operational interruptions. In practice, the degassing zone was then operated in such a way that these amounts of water were removed via the bottom of the degassing column, together with hydrogen chloride, for which the sodium hydroxide-filled towers were required again. If this separation of the water via the bottom of the degassing column were not carried out, the water would be circulated with the recycled vinyl chloride and would lead to corrosion in the plant parts concerned. However, such corrosion is unacceptable not only for economic reasons, but above all for safety reasons.

Es wurde nun gefunden, daß man auf die Natriumhydroxid¬ gefüllten Türme dann verzichten kann, wenn man die Entgasungskolonne so betreibt, daß der Großteil des Wassers über Kopf abgeführt und, zweckmäßig durch Trocknung, entfernt wird. Das in den Prozeß zurückgeführte trockene, Chlorwasserstoffhaltige Vinylchlorid kann dann keine Korrosionen mehr verursachen.It has now been found that the sodium hydroxide-filled towers can be dispensed with if the degassing column is operated in such a way that the majority of the water is discharged overhead and, appropriately, through Drying, is removed. The dry vinyl chloride-containing vinyl chloride returned to the process can then no longer cause corrosion.

Die Erfindung betrifft somit ein Verfahren zur Gewinnung von Vinylchlorid, das dadurch gekennzeichnet ist, daß aus dem bei der unvollständigen thermischen Spaltung von 1,2-Dichlorethan bei erhöhtem Druck und Temperaturen von etwa 450 bis etwa 650 βC in Abwesenheit von Katalysatoren anfallenden Reaktionsgemisch in einer ersten Destillationsstufe der Chlorwasserstoff und in einer zweiten Destillationsstufe das Vinylchlorid abdestilliert wird und wobei das am Kopf der zweiten Destillationsstufe abgezogene und verflüssigte Vinylchlorid teilweise als Rücklauf in die zweite Destillationsstufe zurückgeführt wird und das übrige abgezogene verflüssigte Vinylchlorid dem Kopf einer Entgasungszone zugeführt wird, aus der ein Teil des Vinylchlorids zusammen mit dem gesamten eingeschleppten Chlorwasserstoff und Wasser abgedampft und nach weitgehender Entfernung des Wassers in die erste Destillationsstufe zurückgeführt wird, während dem Boden der Entgasungszone reines Vinylchlorid entnommen wird.The invention thus relates to a process for the production of vinyl chloride, which is characterized in that from the reaction mixture obtained in the incomplete thermal cleavage of 1,2-dichloroethane at elevated pressure and temperatures of about 450 to about 650 ° C. in the absence of catalysts in a first distillation stage, the hydrogen chloride and in a second distillation stage the vinyl chloride is distilled off, and the vinyl chloride drawn off and liquefied at the top of the second distillation stage is partly returned as reflux to the second distillation stage and the remaining liquefied vinyl chloride withdrawn is fed to the top of a degassing zone from which a portion of the vinyl chloride together with all of the hydrochloric acid and water introduced is evaporated off and, after the water has been largely removed, is returned to the first distillation stage while removing pure vinyl chloride from the bottom of the degassing zone will come.

Die Erfindung betrifft weiterhin eine Vorrichtung zur Herstellung von Vinylchlorid mit einer Spaltzone (1) , einer ersten Destillationsstufe (2) für die Abtrennung von Chlorwasserstoff, einer zweitenThe invention further relates to a device for producing vinyl chloride with a cracking zone (1), a first distillation stage (2) for the removal of hydrogen chloride and a second

Destillationsstufe (3) für die Abdestillation von Vinylchlorid von höhersiedenden Bestandteilen und einer dritten Destillationsstufe (4) für die Abtrennung von Chlorwasserstoff und Wasser vom Vinylchlorid, gekennzeichnet durch eine Vorrichtung (5) (Trocknungszone) , über die der in der dritten Destillationsstufe (4) abgetrennte Chlorwasserstoff und Wasser mit Vinylchlorid in die erste Destillationsstufe (2) zurückgeführt und in der das Wasser weitgehend entfernt wird.Distillation stage (3) for the distillation of vinyl chloride from higher-boiling components and a third distillation stage (4) for the separation of hydrogen chloride and water from the vinyl chloride, characterized by a device (5) (drying zone), via which the hydrogen chloride separated in the third distillation stage (4) and water with vinyl chloride are returned to the first distillation stage (2) and in which the water is largely removed.

Die erfindungsgemäße Vorrichtung ist in der Figur schematisch dargestellt. In ihr bedeuten neben den bereits genannten Apparaturen (1) bis (5) :The device according to the invention is shown schematically in the figure. In addition to the devices (1) to (5) already mentioned, they mean:

(6) die Zuleitung für 1,2-Dichlorethan zur Spaltzone (1) ,(6) the feed line for 1,2-dichloroethane to the gap zone (1),

(7) eine Leitung für die Spaltprodukte zur ersten Destillationsstufe (2) , (8) eine Leitung für den abgetrennten Chlorwasserstoff,(7) a line for the cleavage products to the first distillation stage (2), (8) a line for the separated hydrogen chloride,

(9) eine Leitung für die höhersiedenden Produkte zur zweiten Destillationsstufe (3) ,(9) a line for the higher-boiling products to the second distillation stage (3),

(10) eine Leitung zu einem Kondensator (11) für die Verflüssigung des Vinylchlorids,(10) a line to a condenser (11) for the liquefaction of the vinyl chloride,

(12) eine Leitung für einen Teilstrom des verflüssigten Vinylchlorids zurück zur zweiten Destillationsstufe (3) ,(12) a line for a partial stream of the liquefied vinyl chloride back to the second distillation stage (3),

(13) eine Leitung zur Abtrennung hochsiedender Nebenprodukte,(13) a line for separating high-boiling by-products,

(14) eine Leitung für einen zweiten Teilstrom des verflüssigten Vinylchlorids zur dritten Destillationsstufe (4) ,(14) a line for a second partial stream of the liquefied vinyl chloride to the third distillation stage (4),

(15) eine Leitung von der dritten Destillationsstufe (4) zur Trocknungszone (5) ,(15) a line from the third distillation stage (4) to the drying zone (5),

(16) eine Leitung für die getrocknete Mischung aus Chlorwasserstoff und restlichem Vinylchlorid zurück zur ersten Destillationsstufe (2) ,(16) a line for the dried mixture of hydrogen chloride and residual vinyl chloride back to the first distillation stage (2),

(17) eine Leitung für das abgetrennte Wasser und (18) eine Leitung für das reine Vinylchlorid. Bei der erfindungsgemäßen Abtrennung des Wassers tritt in die Trocknungszone ein hochkorrosives Gemisch aus Vinylchlorid, Chlorwasserstoff und Wasser ein. Unter solchen Umständen kann bekanntermaßen eine Polymerisation des Vinylchlorids erfolgen (Katalyse durch Metallspuren) . überraschenderweise konnte jedoch auch bei längerem Betrieb in Metallapparaturen kein Polyvinylchloridbelag festgestellt werden.(17) a line for the separated water and (18) a line for the pure vinyl chloride. When the water is separated off according to the invention, a highly corrosive mixture of vinyl chloride, hydrogen chloride and water enters the drying zone. Under such circumstances, it is known that the vinyl chloride can be polymerized (catalysis by traces of metal). Surprisingly, however, no polyvinyl chloride coating could be found even after prolonged operation in metal equipment.

Die erfindungsgemäße weitgehende Entfernung des Wassers kann in der für saure Fluide bekannten Weise erfolgen. Dies kann durch Kondensation des Wassers, vorzugsweise aber durch Trocknung, beispielsweise mit Mitteln erfolgen, die eine chemische Umwandlung erfahren, beispielsweise flüssige Trocknungsmittel wie konzentrierte Schwefelsäure oder feste Trocknungsmittel wie Phosphorpentoxid oder Calciumchlorid. Bevorzugt sind Trocknungsmittel, die das Wasser adsorptiv festhalten, wie Molekularsiebe und insbesondere Kieselgele.The extensive removal of water according to the invention can be carried out in the manner known for acidic fluids. This can be done by condensing the water, but preferably by drying, for example with agents that undergo chemical conversion, for example liquid drying agents such as concentrated sulfuric acid or solid drying agents such as phosphorus pentoxide or calcium chloride. Drying agents which retain the water by adsorption, such as molecular sieves and in particular silica gels, are preferred.

Die Trocknungszone besteht vorzugsweise aus mindestens zwei parallel geschalteten Trocknern, wobei durch den einen das wasserhaltige zurückzuführende Gemisch geleitet wird, während der andere (oder die anderen) regeneriert beziehungsweise neu beschickt wird (werden) . Es ist natürlich auch möglich, mehrere Trocknungsapparate in Serie zu betreiben. Die bei der Regeneration freiwerdenden Wertstoffe, Vinylchlorid und Chlorwasserstoff, können in das Verfahren zurückgeführt werden.The drying zone preferably consists of at least two dryers connected in parallel, the one containing the water-containing mixture to be recycled being passed through, while the other (or the others) is being regenerated or newly loaded. It is of course also possible to operate several drying devices in series. The valuable substances released during the regeneration, vinyl chloride and hydrogen chloride, can be returned to the process.

In einer bevorzugten Ausgestaltung der Erfindung werden die Trocknungsapparate so ausgestaltet, daß sie zum Regenerieren aufgeheizt und mit einem Inertgas wie Kohlendioxid, einem Edelgas oder vorzugsweise Stickstoff gespült werden können. Geeignet sind beispielsweise Röhren-Wärmetauscher oder Behälter mit innenliegenden Rohrschlangen.In a preferred embodiment of the invention, the drying apparatus are designed so that they are used for Regenerate heated and flushed with an inert gas such as carbon dioxide, an inert gas or preferably nitrogen. Tubular heat exchangers or containers with internal coils are suitable, for example.

Erfindungsgemäß kann der über Kopf der Entgasungskolonne abgeführte Gasstrom getrocknet oder das Kopfprodukt kondensiert und das Kondensat durch den beziehungsweise die Trockner geführt werden.According to the invention, the gas stream discharged via the top of the degassing column can be dried or the top product condensed and the condensate passed through the dryer or dryers.

Zweckmäßig werden die Trockner möglichst nahe an der Entgasungszone installiert, da am Kopf dieser Kolonne die größte Wasserkonzentration herrscht - vor allem dann, wenn die Trocknung der Gasphase erfolgen soll. In diesem Falle kann der Trockner am Beginn der Brüdenleitung installiert sein.The dryers are expediently installed as close as possible to the degassing zone, since the top of this column has the greatest water concentration - especially when the gas phase is to be dried. In this case the dryer can be installed at the beginning of the vapor line.

Wenn auch erfindungsgemäß auf Natriumhydroxid-Türme und dergleichen verzichtet werden kann, so umfaßt dieIf, according to the invention, sodium hydroxide towers and the like can be dispensed with, this includes

Erfindung selbstverständlich auch Ausführungsformen, bei denen - beispielsweise aus Sicherheitsgründen - derartige Vorrichtungen beibehalten werden. In diesem Falle haben diese Vorrichtungen dann erheblich höhere Standzeiten und einen entsprechend verringerten Anfall an Salz und Abwasser.The invention naturally also includes embodiments in which such devices are retained, for example for safety reasons. In this case, these devices have a significantly longer service life and a correspondingly reduced amount of salt and waste water.

Wenn auf die Nachbehandlung mit Natriumhydroxid oder gleichwirkenden Mitteln verzichtet wird, werden nicht nur diese Materialien und die Apparatur eingespart, sondern es entfällt auch der Aufwand mit deren Bedienung und Wartung. Außerdem kann die gesamte Apparatur dann im geschlossenen System betrieben werden. Damit entfallen auch Emissionen beziehungsweise die zu ihrer Vermeidung dienenden Vorkehrungen beim öffnen, Reinigen und Beschicken dieser Apparaturen.If post-treatment with sodium hydroxide or equivalent agents is dispensed with, not only are these materials and the equipment saved, but there is also no need to operate and maintain them. In addition, the entire apparatus can then be operated in a closed system. This also eliminates emissions or the precautions to be taken when opening, cleaning and loading these devices.

Die Erfindung wird in den folgenden Beispielen erläutert.The invention is illustrated in the following examples.

Beispiel 1example 1

Ein Vinylchloridstrom von 39 kg/h mit einem mittleren Wassergehalt von 29,5 ppm wird durch ein Rohr (Länge 200 mm, Durchmesser 80 mm) , gefüllt mit einem Drahtgewebe einer Maschendichte von 125 μm, beschickt mit 740 g Kieselgel (handelsübliches MBlaugel", engporig, 1 bis 3 mm Korngröße) , gepumpt (Druck beimA stream of vinyl chloride of 39 kg / h with an average water content of 29.5 ppm is fed through a tube (length 200 mm, diameter 80 mm), filled with a wire mesh with a mesh size of 125 μm, and charged with 740 g of silica gel (commercially available M Blaugel ", small pores, 1 to 3 mm grain size), pumped (pressure at

Eingang des Rohres 16 bar) . Nach 21 h Laufdauer hat das Kieselgel 15,45 g Wasser adsorbiert, entsprechend einer Beladung von 2,1 Gew.-%. Der Wassergehalt im abströmenden Vinylchlorid beträgt 7,1 ppm.Inlet of the pipe 16 bar). After running for 21 hours, the silica gel adsorbed 15.45 g of water, corresponding to a loading of 2.1% by weight. The water content in the outflowing vinyl chloride is 7.1 ppm.

Zur Desorption wird Niederdruckdampf durch die Apparatur geleitet. Nach 180 min beträgt die Restbeladung des Silicagels < 0,3 %.Low-pressure steam is passed through the apparatus for desorption. After 180 minutes, the residual loading of the silica gel is <0.3%.

Beispiel 2Example 2

In einer technischen Anlage wird ein Vinylchloridstrom von 39 kg/h 19 h durch einen zylindrischen Behälter geleitet. Dimensionierung und Beschickung entsprechen im übrigen dem im Beispiel 1 beschriebenen Behälter. Nach einer Laufzeit von 19 h beträgt die Beladung des Kieselgels 3,07 Gew.-%. Der Wassergehalt des getrockneten Vinylchlorids beträgt 6,5 ppm. Zur Regenerierung wird der Behälter auf circa 120 "C (Innentemperatur) aufgeheizt, wobei ein Stickstoffström von 100 1/h durch die Apparatur geleitet wird. Nach 3 h beträgt die Beladung des Kieselgels 0,25 %.In a technical system, a vinyl chloride flow of 39 kg / h is passed through a cylindrical container for 19 hours. Dimensioning and loading correspond to the rest of the container described in Example 1. After a running time of 19 hours, the loading of the silica gel is 3.07% by weight. The water content of the dried vinyl chloride is 6.5 ppm. For regeneration, the container is heated to approximately 120 ° C. (internal temperature), a nitrogen stream of 100 l / h being passed through the apparatus. After 3 hours, the loading of the silica gel is 0.25%.

Beispiel 3Example 3

In einer technischen Anlage wird ein Vinylchloridstrom von 34 kg/h mit einem mittleren Wassergehalt von 30 ppm durch ein Rohr (Länge 200 mm, Durchmesser 80 mm) , gefüllt mit Molekularsieb (WESSALITH US 330, Firma Degussa, Hanau) , mit einem Druck von etwa 16 bar gepumpt. Nach einer Laufzeit von 88 h hat das Molekularsieb 738 g Wasser adsorbiert, was einer Beladung von 31,9 Gew.-%, bezogen auf das Adsorptionsmittel, entspricht. Nach 23 h Desorption bei 250 °C beträgt die Restbeladung etwa 13 Gew.-%.In a technical system, a vinyl chloride stream of 34 kg / h with an average water content of 30 ppm is fed through a tube (length 200 mm, diameter 80 mm), filled with molecular sieve (WESSALITH US 330, Degussa, Hanau), with a pressure of pumped about 16 bar. After a running time of 88 h, the molecular sieve has adsorbed 738 g of water, which corresponds to a loading of 31.9% by weight, based on the adsorbent. After 23 hours of desorption at 250 ° C., the residual loading is approximately 13% by weight.

Beispiel 4Example 4

Ein Teilstrom des Kopfstroms aus der dritten Destillationsstufe von 0,37 kg Vinylchlorid mit circa 4 g (1000 ppm) Chlorwasserstoffgehalt und circa 6 mgA partial stream of the top stream from the third distillation stage of 0.37 kg of vinyl chloride with about 4 g (1000 ppm) of hydrogen chloride and about 6 mg

(16 ppm) Wassergehalt wird gasförmig abgezogen und über einen Trocknungsapparat geführt. Der Trocknungsapparat besteht aus einem Rohr der Länge 200 mm und einem Durchmesser von 15 mm. Er ist gefüllt mit 35 g Kieselgel (handelsübliches "Blaugel11, engporig, 1 bis 3 mm Korngröße) . Nachdem 100 1 des genannten Gasstroms durch diesen Trockner geleitet wurden, betrug die Beladung des Trocknungsmittels 12,8 Gew.-%. Das austretende Gas enthielt einen durchschnittlichen Wassergehalt von 0,5 ppm. (16 ppm) water content is drawn off in gaseous form and passed over a drying apparatus. The drying device consists of a tube 200 mm long and 15 mm in diameter. It is filled with 35 g of silica gel (commercially available "Blaugel 11 , narrow-pored, 1 to 3 mm grain size). After 100 l of the gas stream mentioned had been passed through this dryer, the loading of the drying agent was 12.8% by weight. The escaping gas contained an average water content of 0.5 ppm.

Claims

Ansprüche Expectations 1. Verfahren zur Gewinnung von Vinylchlorid, dadurch gekennzeichnet, daß aus dem bei der unvollständigen thermischen Spaltung von 1,2-Dichlorethan bei erhöhtem Druck und Temperaturen von etwa 450 bis etwa 650 βc in Abwesenheit von Katalysatoren anfallenden Reaktionsgemisch in einer ersten Destillationsstufe der Chlorwasserstoff und in einer zweiten Destillationsstufe das Vinylchlorid abdestilliert wird und wobei das am Kopf der zweiten Destillationsstufe abgezogene und verflüssigte Vinylchlorid teilweise als Rücklauf in die zweite Destillationsstufe zurückgeführt wird und das übrige abgezogene verflüssigte Vinylchlorid dem Kopf einer Entgasungszone zugeführt wird, aus der ein Teil des Vinylchlorids zusammen mit dem gesamten eingeschleppten Chlorwasserstoff und Wasser abgedampft und nach weitgehender Entfernung des Wassers in die erste Destillationsstufe zurückgeführt wird, während dem Boden der Entgasungszone reines Vinylchlorid entnommen wird.1. A process for the production of vinyl chloride, characterized in that from the incomplete thermal cleavage of 1,2-dichloroethane at elevated pressure and temperatures of about 450 to about 650 β c in the absence of catalysts reaction mixture in a first distillation stage of the hydrogen chloride and the vinyl chloride is distilled off in a second distillation stage, and the vinyl chloride drawn off and liquefied at the top of the second distillation stage is partly recycled as reflux to the second distillation stage and the remaining liquefied vinyl chloride removed is fed to the top of a degassing zone from which part of the vinyl chloride is combined evaporated with all the introduced hydrogen chloride and water and, after the water has been largely removed, is returned to the first distillation stage, while pure vinyl chloride is removed from the bottom of the degassing zone. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Entfernung des Wassers mit Hilfe eines Trocknungsmittels erfolgt.2. The method according to claim 1, characterized in that the removal of the water is carried out with the aid of a drying agent. 3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß ein Trocknungsmittel eingesetzt wird, das das3. The method according to claim 2, characterized in that a drying agent is used, the Wasser adsorbiert.Adsorbs water. 4. Verfahren nach Anspruch 3, dadurch gekennzeichnet, daß als Trocknungsmittel ein Molekularsieb oder Kieselgel eingesetzt wird. 4. The method according to claim 3, characterized in that a molecular sieve or silica gel is used as the drying agent. 5. Vorrichtung zur Herstellung von Vinylchlorid mit einer Spaltzone (1) , einer ersten Destillationsstufe (2) für die Abtrennung von Chlorwasserstoff, einer zweiten Destillationsstufe (3) für die Abdestillation von Vinylchlorid von höhersiedenden Bestandteilen und einer dritten Destillationsstufe (4) für die Abtrennung von Chlorwasserstoff und Wasser vom Vinylchlorid, gekennzeichnet durch eine Vorichtung (5) (Trocknungszone) , über die der in der dritten Destillationsstufe (4) abgetrennte Chlorwasserstoff und Wasser mit Vinylchlorid in die erste Destillationsstufe (2) zurückgeführt und in der das Wasser weitgehend entfernt wird.5. Apparatus for the production of vinyl chloride with a cracking zone (1), a first distillation stage (2) for the removal of hydrogen chloride, a second distillation stage (3) for the distillation of vinyl chloride from higher-boiling components and a third distillation stage (4) for the separation of hydrogen chloride and water from vinyl chloride, characterized by a device (5) (drying zone) via which the hydrogen chloride and water separated off in the third distillation stage (4) and vinyl chloride are returned to the first distillation stage (2) and in which the water is largely removed . 6. Vorrichtung nach Anspruch 5, gekennzeichnet durch einen Trockner, der mit einem Mittel beschickt ist,6. The device according to claim 5, characterized by a dryer which is charged with an agent, -das Wasser physikalisch adsorbiert.-the water is physically adsorbed. 7. Vorrichtung nach Anspruch 5 oder 6, gekennzeichnet durch parallel geschaltete Trockner. 7. The device according to claim 5 or 6, characterized by dryers connected in parallel.
PCT/EP1994/004050 1993-12-09 1994-12-06 Process and device for cleaning vinyl chloride Ceased WO1995015935A1 (en)

Priority Applications (12)

Application Number Priority Date Filing Date Title
DE59405663T DE59405663D1 (en) 1993-12-09 1994-12-06 METHOD AND DEVICE FOR PURIFYING VINYL CHLORIDE
RO96-01138A RO117313B1 (en) 1993-12-09 1994-12-06 Process for purifying vinyl chloride
PL94314878A PL177175B1 (en) 1993-12-09 1994-12-06 Method of and apparatus for purifying vinyl chloride
KR1019960702980A KR100336932B1 (en) 1993-12-09 1994-12-06 Process and device for cleaning vinyl chloride
EP95902128A EP0733031B1 (en) 1993-12-09 1994-12-06 Process and device for cleaning vinyl chloride
JP7515968A JPH09506362A (en) 1993-12-09 1994-12-06 Method and apparatus for purifying vinyl chloride
AU11098/95A AU1109895A (en) 1993-12-09 1994-12-06 Process and device for cleaning vinyl chloride
RU96115265A RU2136651C1 (en) 1993-12-09 1994-12-06 Vinyl chloride production process and installation
UA96072650A UA40639C2 (en) 1993-12-09 1994-12-06 PROCESS for producing vinyl chloride and a mechanism for realizing thereof
HU9601545A HU219385B (en) 1993-12-09 1994-12-06 Process and device for cleaning vinyl chloride
BG100576A BG62484B1 (en) 1993-12-09 1996-05-07 Method and device for vinylchloride treatment
NO962107A NO305550B1 (en) 1993-12-09 1996-05-23 Process and apparatus for the recovery of vinyl chloride

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEP4342042.7 1993-12-09
DE4342042A DE4342042A1 (en) 1993-12-09 1993-12-09 Process and apparatus for cleaning vinyl chloride

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JP (1) JPH09506362A (en)
KR (1) KR100336932B1 (en)
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CZ (1) CZ289769B6 (en)
DE (2) DE4342042A1 (en)
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TW442449B (en) 1996-07-04 2001-06-23 Hoechst Ag Process for preparing 1,2-dichloroethane by direct chlorination
WO2000064847A1 (en) * 1999-04-23 2000-11-02 The Dow Chemical Company Water removal in purification of vinyl chloride
FR2830859B1 (en) * 2001-10-17 2004-06-18 Atofina PROCESS FOR OBTAINING POLYMERIZABLE VINYL CHLORIDE FROM A CRUDE PRODUCT FROM THE PYROLYSIS OF 1,2-DICHLOROETHANE
DE10219723B4 (en) 2002-05-02 2005-06-09 Uhde Gmbh Process for the preparation of unsaturated halogen-containing hydrocarbons and device suitable therefor
DE10319811A1 (en) 2003-04-30 2004-11-18 Uhde Gmbh Device for coupling electromagnetic radiation into a reactor and reactor containing this device
RU2252207C1 (en) * 2003-10-07 2005-05-20 Открытое акционерное общество "Саянскхимпласт" Method for isolation of fine dispersed, gummy and high boiling by-products from dichloroethane pyrolysis reaction gases from vinylchloride production
US8637698B2 (en) * 2010-11-19 2014-01-28 Celanese International Corporation Production of acetic acid with an increased production rate
CN102675034B (en) * 2012-05-10 2014-05-14 江苏省计量科学研究院 System and method for purifying vinyl chloride monomer
CN103694079B (en) * 2013-09-27 2015-04-15 新疆天业(集团)有限公司 Method for refining and purifying vinyl chloride monomer
CN105481640B (en) * 2015-12-17 2019-03-08 青岛科技大学 A kind of vinyl chloride rectification process with low energy consumption and low loss
TWI832422B (en) * 2022-09-14 2024-02-11 臺灣塑膠工業股份有限公司 System and method for producing vinyl chloride

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CZ165096A3 (en) 1996-09-11
SG64916A1 (en) 1999-05-25
EP0733031B1 (en) 1998-04-08
KR960706463A (en) 1996-12-09
SA94150394B1 (en) 2005-06-15
IL111907A0 (en) 1995-03-15
RO117313B1 (en) 2002-01-30
BG100576A (en) 1997-02-28
HU219385B (en) 2001-03-28
PL314878A1 (en) 1996-09-30
IL111907A (en) 1998-06-15
MY116481A (en) 2004-02-28
HUT74047A (en) 1996-10-28
KR100336932B1 (en) 2002-11-23
US5507920A (en) 1996-04-16
HU9601545D0 (en) 1996-08-28
TW316894B (en) 1997-10-01
DE59405663D1 (en) 1998-05-14
UA40639C2 (en) 2001-08-15
CN1046496C (en) 1999-11-17
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AU1109895A (en) 1995-06-27
ES2116711T3 (en) 1998-07-16
BG62484B1 (en) 1999-12-30
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ZA949784B (en) 1995-07-11
NO305550B1 (en) 1999-06-21

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